Hot gas outlet thimble



Nov. 6, 1945. R. c. WRIGHT HOT GAS OUTLET THMBLE Filed April 8, 1944- 2 Sheets-Sheet 2 f/vyf/VrO/P 6 Www/7- .Erw

Patented Nov. 6, 1945 UNITED STATE Hor GAS OUTLET THIMBLE Richard C. Wright, Bay Village, Ohio, assigner to Iron Fireman Manufacturing Company, Portland, Oreg.

Application. April 8, 1944, Serial No. 530,219'

3 Claims.

This invention relates generally to burners or furnaces, and particularly to a hot gas outlet thimble to be used in conjunction therewith.

The main object of this invention is to provide a suitable connection for withdrawing hot furnace gases through a refractory wall from a furnace in which fuel is Ibeing burned.

The second object is to provide suitable means forv supporting the end of a conduit within which the gases are conveyed from the furnace.A f

Thefth-ird object is to prevent excessive overheating of the end of the conduit, and to proride an expansion joint therefor.

The fourth objectis to provide means for regulating the temperature of the gases in the conduit by diluting them with air from the `Sur-- rounding atmosphere.

These and other objects will become more ap'- parent from the speei-cation following as illustrated in the accompanying drawings, in which:

Fig. l is a fragmentary View of a representative form of furnace installation showing a Iboiler setting broken away in section.

Fig. 2 is a plan of the device with parts broken away in section.

Fig. 3 is a front elevation of the device with parts broken away.

Referring in detail to the drawings, there is shown a furnace front I0, grates I I, tubes I2, and fire door I3 of a conventional type of installation. There is also indicated the fuel delivery pipe I4 through which solid fuel is conveyed pneumatically and discharged through the tip I5 extending through the opening I6 of the wall I0. Above the opening I6 is disposed the opening- I1 which extends through the wall Ill to receive the hot gas thimble', which I am about to describe.

Referring more particularly to my invention, same will be seen to consist of a cylindrical thimble I8 having a flanged rim I9 from which project the ears with holes 2| for anchor bolts not shown, which are anchored in the wall I0. It is preferable to provide ribs 23 behind the ears 20 for the purpose of stiffening the ears and also to resist rotation of the sleeve I8 within the opening I1.

Extending inwardly from the ange I 9 are the projections 24 whose sides 25 are radial and whose edges 26 are arcs of a circle concentric with the thimble I8. Longitudinal ribs 21 and 28 reinforce the projections 24 and the edge 29 of the rib 21 projects slightly beyond the arcuate edge 26. The ribs 28 may be somewhat lighter than the ribs 21 and need not project beyond the arcuate surfaces 26 of their respective projections 24, the purpose of this construction being to hold the hot gas pipe 38-concentric withk relation to the thimble I8 and yet hold it out or engagement with the `edge* 26 upon which-it would ordinarily rest.

Referring now to the movable member of 'the device, same will be seen to consist of a valve plate SlT-A having a `central opening 3l which extends generally to the inner edge 32 whieh`eonforms with the interior of the thimble i8. The edge 32 has extending therefrom the inturned projections 33 which are sufficient to bridge the gaps-'between the radial sides 25 of the projections 24. The inner edges 3ft of the projections 33' are formed on the same radii as are the inner vedges 2S of the projections 2d. Formed in the periphery of the plate 38'- are a plurality of arcnate slots 35 adapted to freely receive the bolts 36 which are threaded into the tapped openings 31 in the flange I9.

It can be seen from the foregoing that with this construction, the hot gas pipe 30 is held along the axis of the opening I1 by means of the supporting projections 21 and 28 which are cooled by the air drawn in throughthe openings. It will also be seen that by means of this construction the temperature of the gases passing through the pipe 38 may be easily controlled as Well as the proportion of air and partially or fully burned gas, by merely rotating the plate 3IJA at the same time affording an expansion joint, a pipe support and a cold air mixing thimble all in two simple castings, and also provides a way of admitting the cold air to the intake end of the hot gas pipe so as to cool its entire length, in addition to rendering it unnecessary to accurately cut the hot gas pipe for length when installing same.

When installing this thimble, the opening I1 should be located as high as possible in the front boiler wall I0 and as close to the center as practical.

. The thimble should be installed in the furnace wall in such a position that it will act as an expansion joint and the end of the hot gas pipe 30 should not extend into the casting I8 more than three inches.

It is desirable to provide a ring of plastic refractory material 38 around the inlet I1 to shield the pipe 30 and the thimble casting I8 from the direct, radiant heat of the furnace. The lower part 39 of the ring 38 should be sloped as indicated in Fig. 1 to permit entrance of a cleaning tool to remove any accumulation of slag that may form over the opening.

When installing this thimble, care should be taken that the heavier supporting web 21 is located at the bottom, that is, the underside of the pipe 3U. Care should be taken to see that the pipe 30 rests freely upon the edge 29 of the web 21, and that there is suiicient clearance for expansion when the pipe 30 is heated.

A slag drip 40 should be provided by allowing one course of the fire brick above the intake opening Il to project about two inches into the furnace, thereby preventing the slag fromaccumulating around the opening IT.

While I have thus illustrated and described my invention, it must be understood that I do not wish to be limited to the precise details shown herein, but I intend to cover all such forms and modifications therein as fall fairly within the appended claims.

I claim:

1. A device of the class described, consisting of a cylindrical thimble, a flange extending inwardly and outwardly from said thimble the inwardly extending portion of said ange being cut away at spaced intervals, a circular disc having a circular opening formed therein substantially equal to the opening in said ilange, said disc having spaced cut-out portions in said flange when said disc is loaded with relation thereto, said thimble having radial ribs on the interior thereof, the lowermost one of which extends above the lowermost interior edge of said disc, and means for xing the relationship between said disc with relation to said ilange.

2. In a device of the class described, the combination of a cylindrical thimble having a flange at one end thereof extending outside of and inside of Said thimble n0rma1 to the axis or the thimble, a hot gas pipe extending axially through said thimble and flange, radial ribs within said thimble extending to the interior of said ange, the lowermost rib constituting a support for said 'gas pipe, the innermost portion of said Lflange having cut-away portions spaced from each other and extending from the exterior of the gas pipe to the interior of said thimble, a disc rotatably mounted against said flange having a central opening substantially the same as that of said flange, and bolts extending through said disc and flange whereby the relative relation of said disc and flange may be xed.

3. In a fluid conveying system, the combination of a refractory wall constituting a boiler front and having an opening therethrough together with a cylindrical thimble mounted in said opening and having a flange on the outer end thereof extending outwardly and inwardly from said thimble in a plane normal to its axis, a disc constituting a closure for said thimble having means for revolvably mounting same thereon and securing its position with relation thereto, a hot gas pipe extending through said disc and inner flange portion extending part way into said thimble, the portions of said disc and flange immediately surrounding said gas pipe having cutout portions adapted to register when said disc is turned to a given position, said thimble having radial internal ribs extending to the internal edges of said disc and innermost ilange portions, the lowermost rib constituting a support for said hot gas pipe, the end of Vsaid boiler front opening nearest the combustion chamber having a restricted inlet communicating with said hot gas inlet, said furnace front having a slag drip formed above said restricted opening spaced from the interior face of the furnace front. l

RICHARD C. WRIGHT. 

